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Steven Lord


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MathWorks

3 949 total contributions since 2002

I joined The MathWorks in the Technical Support department during the summer of 2001 and transferred into the Quality Engineering department in March of 2004. I now work qualifying the core MATLAB numerical functions (PLUS, MINUS, LU, FFT, ODE45, etc.)
Professional Interests: mathematics, MATLAB

For assistance with MATLAB question please post to MATLAB Answers or contact Technical Support using the Contact Us link in the upper-right corner of the page instead of contacting me directly.

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Answered
Is the time vector t for the function odefun() inside ode45() always required?
From the documentation page for the ode45 function "The function dydt = odefun(t,y), for a scalar t and a column vector y, must ...

environ une heure ago | 0

Answered
How to use ode45 for a row vector
See the "Pass Extra Parameters to ODE Function" example on the documentation page for the ode45 function. You can use it as a mo...

environ une heure ago | 0

Answered
How to open matlab app designer in MATLAB 2020 ?
App Designer and Polyspace aren't really related. App Designer is still present in MATLAB release R2020a, and the Polyspace fami...

environ 10 heures ago | 0

Answered
why does matlab tell me that the "chop" command doesn't exist?
Cleve's original version of MATLAB had a chop command as you can see from the user's guide, but I'm not sure there is such a com...

1 jour ago | 0

Answered
Query regarding the colon operator
The a variable is a 6-dimensional array. The part you're showing spans all the rows (the first colon) and all the columns (the s...

1 jour ago | 0

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Answered
Spherical coordinates to cartesian
From the documentation "azimuth is the counterclockwise angle in the x-y plane measured in radians from the positive x-axis." an...

1 jour ago | 0

Answered
calculate week of year
Since the original question was written, we introduced datetime. If you're representing your time and date data as a datetime, c...

2 jours ago | 0

Answered
OSError: MATLAB Engine for Python supports Python version 2.7, 3.5 and 3.6 but your version of Python is 3.7
Support for Python 3.7 was added in release R2019a. The Release field to the right of this question indicates you're using relea...

2 jours ago | 0

Answered
How to create a vector with elements randomly chosen from another vector?
I have a column vector, each of whose elements is a row vector consisting of two elements The common term for that is a matrix....

2 jours ago | 0

| accepted

Answered
Index in position 2 exceeds array bounds (must not exceed 5).
Rather than trusting your user to enter a value of n compatible with the sizes of A and b, compute it from A and/or b using size...

4 jours ago | 0

Answered
Problem with data type: calculate [HH:mm:ss.FFF]
Convert the text representations of those values into a duration array then call seconds on the duration array.

4 jours ago | 0

Answered
I want to install 2020 matlab win32
The last release of MATLAB that was supported on a 32-bit Windows OS was release R2015b. You will need to be running a 64-bit ve...

5 jours ago | 0

Answered
Access automatically substructures from loop
Rather than depending on the order in which the fields of the struct array are displayed (which can change -- in the following e...

5 jours ago | 0

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Answered
toolbox installastion for matlab
Use the Add-Ons functionality to add this File Exchange submission to your MATLAB installation.

5 jours ago | 0

Answered
What is z1 appearing when solving this nonlinear system for x y and z?
Theoretically you could write out the roots of a quartic equation. There's a picture on the Wikipedia page for quartic function ...

5 jours ago | 1

Answered
Integrating: I keep getting 'Array indices must be positive integers or logical values.'
You have y(1+x.^2) inside the second term of Fun. That is an attempt to index into y, but you probably intended it to be y times...

6 jours ago | 0

Answered
hi hi hi hi
The third input argument to ode45 is the vector of initial conditions and the fourth is the options. You're trying to pass vecto...

6 jours ago | 0

Answered
Subroutines stops at input
I advise you not to create 26 individual variables and replicate almost exactly the same code 26 times for each operation you wa...

7 jours ago | 0

Answered
How to decipher date formats?
It depends. Is that first date supposed to be: the 9th of January, 2019 (day/month/year, increasing order of size of units) th...

7 jours ago | 0

Answered
Gapless 2d color plot
The problem with pcolor() would be, that the x and y values are always 1,2,3,4,5 and so on. That's because you called pcolor wi...

8 jours ago | 1

Answered
How to write if else program on matlab?
elseif (0<power<=1000) This doesn't do what you think it does. If you're writing this code in the MATLAB Editor and you're usin...

10 jours ago | 1

Answered
Creating Caps to close a tubular structure
It sounds like you want isocaps. See this documentation page for more information.

10 jours ago | 0

Answered
Graph plotting HELP NEEDED
If you're trying to create a plot that has a particular appearance but you're not sure which function can create such a plot, op...

10 jours ago | 0

Answered
isempty: Not enough input arguments.
The problem is not that the field z of x.y is empty. The problem is that the field y of x is. In the example below, due to the b...

10 jours ago | 1

| accepted

Answered
converting sym to double
Make K a sym array from the start. Then MATLAB doesn't need to convert the symbolic expression 0.7499*k when assigning into an e...

11 jours ago | 0

Answered
Naming a struct with a variable?
2 isn't a valid struct array field name. But you can do something like your second alternative using dynamic field names. S = s...

11 jours ago | 1

Answered
How to add a colormap manually as x-axis under an histogram?
Call colorbar with the 'southoutside' location as shown in the "Add Horizontal Colorbar to Graph" example on the documentation p...

11 jours ago | 0

| accepted

Answered
Debug /pause at every function definition line (local function or function script) without explicit breakpoints
There's no way to say "stop whenever a new function gets called" in debug mode without setting breakpoints. But if you're debug...

11 jours ago | 0

| accepted

Answered
How can I do this in MATLAB?
Put the cursor on the function whose definition you want to open. Right-click and select "Open <name of function>". There's a ke...

11 jours ago | 1

| accepted

Answered
Getting rid of goto()-messes due to inconsistencies
Your mindmap has your problem broken up into small chunks. That's the first step towards modularizing your code. As you correctl...

12 jours ago | 0

| accepted

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